Sacrificial Anode Mass Calculator
For corrosion engineers designing marine pipelines or offshore structures who need a rapid, DNVGL-RP-B401 aligned preliminary mass estimate before commissioning full electrochemical CP models. This tool computes the exact sacrificial anode mass (in kg) required for a specified protection life.
Disclaimer: This tool provides preliminary estimates only, not a substitute for review by a qualified/licensed engineer.
How to Use This Calculator
- Enter the total required protection current in amperes.
- Input the target system design life in years.
- Set the anode utilization factor as a decimal (DNV-RP-B401: 0.80 to 0.90 depending on anode shape).
- Provide the specific electrode capacity in ampere-hours per kilogram.
- Click Calculate to instantly display the minimum anode mass required.
FAQ
Q: How does DNVGL-RP-B401 define the utilization factor for zinc anodes?
A: Table 10-8 of DNV-RP-B401 gives 0.90 for long slender stand-off anodes, 0.85 for short stand-off and long flush-mounted anodes, and 0.80 for short flush-mounted, bracelet and other types, whatever the alloy.
Q: Why multiply time by 8760 in the anode mass formula?
A: Because 8760 equals the exact number of hours in a non-leap calendar year (365 × 24), ensuring the calculation reflects continuous DC discharge over the full design period.
Q: Can this calculator account for ceramic coating thickness losses?
A: No; it follows strict DNVGL-RP-B401 primary mass calculations without geometric derating. Adjust the capacity input downward if specified, or run dimensional checks in the Galvanic Anode Output Current tool.
Q: What capacity value should I use for high-potential aluminum anodes?
A: For design, DNV-RP-B401 Table 10-6 gives 2,000 Ah/kg for aluminium-based anodes in seawater (1,500 in sediments) and 780 Ah/kg for zinc. Laboratory tests often report 2,500 Ah/kg or more, but DNV recommends the design values.